Spectroscopic properties of Eu3+ in lanthanum chlorotungstates

The spectroscopic properties of Eu3+ doped into two lanthanum chlorotungstates matrices, namely LaWO4Cl (1-1) and La3WO6Cl3(3-1), are investigated. The fluorescence spectra of these compounds, recorded at room and liquid nitrogen temperatures, show that the lanthanide ion occupies only one site with the low symmetry, Cs, in both cases. From the energy level schemes of the 7FJ levels (J = 0, 1, 2, 3, 4, 5), two sets of crystal field parameters (cfp) are deduced, in a C2v approximated point symmetry (i.e., 9 cfp), simulating the experimental data, correctly. Furthermore, for the 3-1 compound, the data is complete enough to extend the calculations to the real point group, Cs (14 cfp).